Cognitive models of insomnia highlight the role of biased cognition in sleep‐related information, which is proposed to underlie pre‐sleep worry, which in turn results in both subjective and objective sleep deficits. To test this hypothesis, the current study investigated interpretational bias, which is a tendency to interpret ambiguous stimuli in a threat‐related (here: insomnia‐related) manner. We specifically hypothesized that interpretational bias would be associated with (a) pre‐sleep worry and (b) poor subjective and objective sleep. Interpretational bias was measured using the ambiguous scenario task, in which participants (n = 76, community sample) were presented with two types of scenarios (insomnia and anxiety related) that could be alternatively interpreted in a neutral manner. Participants additionally completed questionnaires to assess global sleep quality and pre‐sleep worry, which were followed by 1‐week sleep assessments (via diaries and actigraphy) to estimate specific, daily subjective and objective sleep parameters. The results showed that insomnia‐related (but not anxiety‐related) interpretational bias was positively associated with pre‐sleep worry as well as overall sleep quality. However, these associations could be explained by general trait anxiety. We also found no connection to specific subjective or objective parameters of daily sleep, such as sleep onset latency. These findings support the cognitive‐hyperarousal mechanism, where biased cognition (together with trait anxiety) underlies pre‐sleep worry. The association with overall sleep quality, but not with specific, daily subjective or objective sleep parameters, may suggest that interpretational bias is specifically relevant for how individuals judge and describe their sleep quality.